Testosterone Test in Australia

What a testosterone test measures

A testosterone test measures the concentration of testosterone in serum. Most Australian requests measure total testosterone, and pair it with SHBG and albumin so that calculated free testosterone — the fraction not tightly bound to carrier proteins — can be worked out.

Almost all testosterone in the bloodstream is bound. Roughly 40 to 60 per cent is bound tightly to sex hormone-binding globulin (SHBG), most of the remainder is bound loosely to albumin, and only 1 to 3 per cent circulates unbound. Total testosterone counts all of it. That matters, because anything that shifts SHBG shifts the total without necessarily changing the biologically available fraction at all.

SHBG rises with age, thyroid overactivity, liver disease, oral oestrogen and some anticonvulsants. It falls with obesity, insulin resistance, type 2 diabetes, corticosteroids and hypothyroidism. A man with a low SHBG can therefore show a total testosterone below the reference interval while his calculated free testosterone sits in the normal range — and a man with a high SHBG can show the reverse. This is why Australian laboratories commonly report SHBG and albumin alongside the total, and derive calculated free testosterone (usually by the Vermeulen equation) rather than measuring it directly.

Direct 'free testosterone' immunoassays are widely regarded as unreliable and are not the preferred approach in Australian laboratories; equilibrium dialysis is the reference method but is rarely available outside specialist settings. Calculated free testosterone from a reliable total assay plus SHBG is the practical standard.

When a total testosterone is repeatedly low, a doctor will usually add luteinising hormone (LH) and follicle-stimulating hormone (FSH), and often prolactin. LH and FSH show whether the signal from the pituitary is high (suggesting the testes are not responding) or low or inappropriately normal (pointing upstream to the pituitary or hypothalamus). Prolactin is checked because a prolactin-secreting pituitary tumour is an uncommon but important and specifically manageable finding. These are investigative steps directed by a doctor, not something a result alone settles.

Why testosterone is measured

Testosterone is measured to investigate symptoms or clinical findings that may relate to androgen status — in men, features suggesting androgen deficiency; in women, features suggesting androgen excess.

In men, the symptoms that prompt testing are notoriously non-specific: persistent fatigue, low mood, reduced libido, erectile difficulties, loss of morning erections, reduced muscle mass, increased body fat, poor concentration and disturbed sleep. Each of these has many possible explanations, and the majority turn out not to be hormonal. Australian guidance is consistent that testing should follow genuine clinical suspicion rather than curiosity, and that a result should always be read against the person in front of the doctor.

There are also findings that make a hormonal cause more likely and warrant measurement regardless of how a man feels: small or shrinking testes, loss of body hair, breast tissue development, infertility, unexplained osteoporosis or low-trauma fracture, and a history of undescended testes, mumps orchitis, testicular trauma, chemotherapy, radiotherapy or pituitary disease.

In women, testosterone is measured for the opposite reason — suspected androgen excess. Irregular or absent periods, excess facial or body hair, persistent acne, scalp hair thinning and difficulty conceiving may prompt a panel that includes total testosterone and SHBG, often with LH, FSH, prolactin and thyroid function, as part of assessing possible polycystic ovary syndrome. A markedly raised testosterone in a woman, particularly with rapid onset, is a finding that needs prompt specialist review.

Testosterone is also measured in men already under a doctor's care for a known endocrine condition, as part of that doctor's monitoring. FORM's role in that situation is limited to providing the bloodwork and a written interpretation you take back to that doctor.

• Reduced libido, erectile difficulties or loss of morning erections.
• Persistent fatigue, low mood or poor concentration without another explanation.
• Loss of muscle mass, reduced strength or increased central body fat.
• Small or shrinking testes, reduced body hair, or breast tissue development.
• Difficulty conceiving, or an abnormal semen analysis.
• Unexplained osteoporosis or a fracture from a minor injury.
• In women: irregular periods, excess hair growth, persistent acne or scalp hair thinning.

What a high result can indicate

A raised testosterone means very different things in men and in women, and the first question a doctor asks is whether anything is being taken that contains or raises androgens.

In men, a total testosterone above the reference interval is uncommon in the absence of an exogenous source. Androgenic or anabolic preparations — including products sold online, in gyms or as 'supplements' with undeclared ingredients — are the usual explanation, and Australian analyses have repeatedly found undisclosed hormonal compounds in unregulated products. Less commonly, a high result reflects an androgen-secreting tumour, congenital adrenal hyperplasia, or simply a high SHBG lifting the total while the free fraction is ordinary.

Exogenous androgens characteristically suppress LH and FSH to very low levels, because the pituitary reads the circulating androgen and stops signalling. That pattern also suppresses sperm production, which is why unexplained infertility in a man with a high testosterone and flat gonadotrophins is a recognised presentation. If this applies to you, tell your doctor exactly what you have taken — the conversation is confidential and it changes what the numbers mean.

In women, a total testosterone modestly above the female interval is most often associated with polycystic ovary syndrome, which is a clinical diagnosis made on defined criteria and never on a hormone level alone. A substantially raised level, especially with rapid virilisation, points towards an ovarian or adrenal source and needs urgent specialist assessment rather than repeat testing.

What a low result can indicate

A single low testosterone is a prompt to repeat the test, not a conclusion. Australian practice requires at least two low morning fasted samples, taken on separate days, before androgen deficiency is even considered.

Testosterone follows a strong daily rhythm, peaking in the early morning and falling by 20 to 25 per cent or more by late afternoon in younger men. It also drops transiently during any acute illness, after poor sleep, after heavy alcohol intake and during periods of significant physical or psychological stress. A single afternoon sample taken during a flu is close to meaningless, and repeating a low result on a second morning is the single most useful next step.

Where a low level is confirmed, the commonest contributors in Australian men are reversible or coexisting conditions rather than primary testicular failure: obesity and metabolic syndrome, obstructive sleep apnoea, type 2 diabetes, excess alcohol, opioid analgesics, long-term corticosteroids, chronic illness and severe under-eating or overtraining. Addressing those is a matter for your doctor, and often changes the numbers substantially on retesting.

Genuine androgen deficiency is classified by where the problem sits. Primary (testicular) causes show low testosterone with raised LH and FSH, and include Klinefelter syndrome, prior mumps orchitis, testicular trauma, chemotherapy and radiotherapy. Secondary (pituitary or hypothalamic) causes show low testosterone with low or inappropriately normal LH and FSH, and include pituitary tumours, raised prolactin, haemochromatosis and the functional suppression seen with obesity, opioids or serious illness.

What happens next is entirely a medical decision. FORM does not prescribe, supply or arrange testosterone, and nothing on this page should be read as a recommendation for or against any therapy. Take your report to your GP or an AHPRA-registered doctor, who can examine you, consider the whole picture, arrange further investigation and advise you on what — if anything — should be done.

Australian reference ranges and units

Australian laboratories report testosterone in nanomoles per litre (nmol/L), not the ng/dL used in the United States. To convert, divide a ng/dL figure by roughly 28.8.

Reference intervals are assay-specific and vary between Australian laboratories, so always read your result against the interval printed on your own report. The figures below are indicative intervals compiled from the RCPA Manual, Lab Tests Online AU and Australian consensus guidance, and are provided so you can orient yourself before speaking with a doctor.

Who should consider testing

Testing is most useful when there is a specific question to answer — a persistent symptom, a clinical finding, or a doctor's request for monitoring — rather than as a number collected out of interest.

If your symptoms include chest pain, sudden severe headache, visual field loss, collapse or rapidly progressive weakness, seek urgent medical care rather than ordering a blood test. FORM does not provide emergency or acute care.

• Men with persistent, unexplained fatigue, low libido or erectile difficulties that have lasted months.
• Men with reduced testicular size, reduced body hair or breast tissue development.
• Men investigating fertility, or with an abnormal semen analysis.
• Men with type 2 diabetes, obesity, obstructive sleep apnoea or long-term opioid or corticosteroid use, where a doctor has raised the question.
• Men with unexplained osteoporosis or a low-trauma fracture.
• Women with irregular periods, excess facial or body hair, persistent acne or scalp hair thinning, as part of a broader hormone panel.
• Anyone whose doctor has asked for baseline or follow-up bloodwork and prefers to have it collected without waiting for another appointment.

How testing works with FORM

You order online, we issue an Australian pathology request form, you attend an accredited collection centre, and you receive your results in SI units with a written plain-English interpretation to take to your own doctor.

No GP referral is required. Australian pathology laboratories can accept requests from a range of approved requesters, and patient-requested pathology is legal and established here — the practical difference is that patient-requested testing is not eligible for a Medicare rebate, so you pay the full cost. We say that plainly up front rather than in the fine print.

Collection happens at accredited (NATA / ISO 15189) pathology centres, which exist in every capital city and most regional centres. For testosterone we ask you to book a morning slot and to fast beforehand, because collection timing affects the result more than almost anything else you can control. If your first result is low, the standard next step is a repeat morning fasted sample on a separate day.

Your report presents each measurement in the units Australian laboratories use, alongside the laboratory's own reference interval, with an explanation of what the pattern across total testosterone, SHBG and calculated free testosterone does and does not show. It is written so you and your doctor can read the same document and have a productive conversation.

To be explicit about scope: FORM is a pathology testing service. We do not prescribe, supply or arrange testosterone or any other medicine, we are not a substitute for medical care, and we do not provide treatment. Any decision about therapy is made by an AHPRA-registered doctor who has assessed you.